This invention relates to the formation of a nickel foil using electrodeposition from a nickel plating bath. More particularly, this invention relates to the formation of a nickel foil with controlled permeability to hydrogen by electrodeposition of a nickel layer from a nickel plating bath.
In the prior art, it is known to electrodeposit nickel from a nickel plating bath containing an organic sulfonic acid. Illustrative of this type of prior art is U.S. Pat. No. 2,112,818 to Waite, U.S. Pat. No. 2,198,267 to Lind et al., U.S. Pat. No. 2,467,580 to Brown, U.S. Pat. No. 2,513,280 to Brown, U.S. Pat. No. 3,594,288 to Reinert, "Nickel Plating from Sulfamate Solutions Part III," Metal Finishing Journal, p. 234 (August 1970) by Hammond, and "The Effects of Some Variables Upon Hardness of Sulfamate Nickel Deposits," presented at the International Symposium on the Uses of Sulfamic Acid, Milan, Italy (1967) by Marti et al., Barrett Chemical Products Division, Allied Research Products, Incorporated, Detroit, Mich. Reinert, in addition, shows that it is known to electrodeposit a nickel layer onto stainless steel using a nickel sulfamate plating bath containing a naphthalenetrisulfonic acid, and Hammond and Marti et al. use 1,3,6-naphthalenetrisulfonic acid in a nickel sulfamate bath. Also known is the codeposition of sulfur as an occlusion with nickel, with this type of art being exemplified by Konishi, "Duplex Nickel Plating," Metal Finishing, Vol. 63, p. 67 (April 1965).
In none of this art and in none of the prior art of which I am aware, is an organic sulfonic acid added to a nickel plating bath in a selected concentration to form a nickel foil having a predetermined hydrogen permeability. Rather, organic sulfonic acids such as 1,3,6-naphthalenetrisulfonic acid are used to promote stress reduction and hardness by incorporating sulfur in the deposit as occlusions. Also, organic sulfonic acids are used in order to electrodeposit a bright ductile nickel plate.
It is also known to use coumarin as a leveling agent in a nickel plating bath. This type of prior art is illustrated by U.S. Pat. No. 3,677,913 to Passal, and Rigers et al., "The Effects of Coumarin on the Deposition of Nickel," Electrochemica Acta, Vol. 8, p. 887 (1963). Furthermore, removal of melilotic acid contaminant, a reduction product of coumarin, from a nickel plating bath by use of a cation exchange resin is known, as exemplified by Wu et al., "Automatic Purification of Coumarin-Containing Nickel Plating Baths," Plating, Vol. 59, p. 1033 (Nov. 1972).
In none of this art and in none of the prior art of which I am aware, is there a process for forming a nickel foil with controlled and predetermined permeability to hydrogen.
With the current energy shortage, hydrogen is of interest as a means of delivering energy from non-fossil primary energy resources such as nuclear, geothermal and solar energy conversion processes. Hydrogen can be produced from water by means of one or more water-splitting processes such as water electrolysis. Key problem areas in using hydrogen to deliver energy include production, storage and transmission. For the production, transfer or storage of hydrogen, a material with a high permeability to hydrogen is often desired. Palladium is such a material, and although it is very expensive, it is often employed for these purposes. Thus, there is a need for a less expensive material having high hydrogen permeability that can be used for the production, transfer or storage of hydrogen. Also, there is a need for a reproducible process to produce a material of this type.